Rivet



March 20, 1951 w, w SINGLETQN 2,545,752

RIVET Filed Aug. 9, 1946 I TIIIIIIg/IIILIf/fi Fig.4-

III/[1111,14,]; A

IN V EN TOR.

[WILL/AM W SINGLE TON ATTORNE V Patented Mar. 20, 1951 RIVET William W. Singleton, Detroit, Mich., assignor to Bendix Aviation Corporation, Detroit, Mich, a

corporation of Delaware Application August 9, 1946, Serial No. 689,493

1 This invention relates to rivets. An object of the invention is the provision 01 a double grip rivet especially adapted for use on dual wall structures, and which serves as a spacer between the two wall elements.

Another object of the invention is to provide an'expandable hollow rivet for double wall construction,which may be inserted through aligned openings of equal diameter in the wall elements.

A further object of the invention is to provide a double grip hollow rivet which may be set in a single pulling operation without the necessity for backing or hammering.

A still further object of the invention is to provide a double grip rivet which may be secured in place by manipulation from one side only.

Yet a still further'object of the invention is the provision of a double grip hollow rivet to be expanded in place by a forming mandrel drawn into the rivet and permanently contained therein to provide additional strength and rigidity.

Other objects and advantages of the invention will appear from the following description taken in connection with the accompanying drawings forming a part of this application, and in which--- Fig. 1 is a partial section view of the assembled rivet after it has been expanded in place and the forming mandrel severed flush with the formed head.

Fig. 2 is a partial section view showing the pulling pin and sleeve in place within the hollow rivet.

Fig. 3 is a partial section view similar to Fig. 2,

except that a gripping head has been formed on the pulling pin; and

Fig. 4 is an exploded View of the rivet assembly showing the tension member in elevation and the sleeveand rivet body in section.

Referring to the drawings for more specific details of the invention It] represents a rivet body having a shank l2 and an enlarged pre-formed head l4 on one end thereof. The rivet body It! has a, double diametral axial bore therethrough providing therein an annular tapered shoulder [6 adjacent the rivet head 14. The larger bore I8 is contained within the rivet shank I2 and the smaller bore 2|] extends through the rivet head [4. The tapered shoulder I6 provides a seating abutment to support an expandable cylindrical sleeve 22 adapted to be fitted into the bore l8. This sleeve 22 has an axial bore 24 slightly larger in diameter than the bore 20 in the rivet head and an over all length substantially less than that of the counterbored section l8. Both therivet body It and sleeve 22 are formed of 8 Claims. (01. s 40) a ductile material, such as an aluminumalloy, which also has the necessary strength in tension, compression and shear.

To complete the rivet assembly a compression member is provided consisting of a, duplex forming mandrel 26 and a pulling pin 28. As the diameter of the pulling pin is slightly less than that of the borein either the sleeve 22 or therivet body ID, a complete rivet assembly, as shown in Fig. 2, may be readily provided. To prevent. the component parts from becoming separated. from the rivet assembly, an engagement head.

.30 is formed at the free end of the pulling pin.

28. This head 30 also serves as a, means of ap-- plying the force necessary to position the man-- drel 26, as shown in Fig. 1. The mandrel 26 is formed from a light weight material, such as: an aluminum alloy, having a high tensile strength to withstand the stress imposed during the pulling operation.

To improve the general properties of the var-- ious elements comprising the rivet assembly, an annodyzing treatment is applied. This forms a. porous and abrasive resistant coating over the surface thereof, which, when impregnated with a rust inhibitor such as chromic acid, becomes virtually immune to corrosion.

To reduce the frictional drag, which occurs between the rivet elements when the forming mandrel 26 is drawn into position, all sliding" surfaces are lubricated with stearic acid, paraffin or any other suitable anti-friction compound. Thispractice, together With that of annodyzing the complete rivet assembly, prevents the forming mandrel 26 from sticking and thus insures a proper seating of each rivet.

In use, the rivet assembly previously described in detail, is especially adapted for the fabrication of double walled structures or panels, as illustrated in Fig. 1. Two spaced wall members, such as 32 and 34 are provided with aligned openings adapted to receive the complete rivet assembly shown in Fig. 3. This assembly may be inserted from one side only, a feature which makes it adaptable for use where blind riveting is required.

The length of the rivet selected must always be adequate to extend beyond the inner wall member 32 and thus provide a portion of the rivet body ID, from which to form a tail enlargement 36. The thickness of the wall members 32 and 34 must also be considered in the proper selection of a rivet, as it is this feature which governs the depth of the counterbore ill. The tapered annular shoulder H5 at the bottom thereof should always'fall approximately at the inner surface;

the rivet body or establish a sharp radius of v curvature at either end of the bulbou enlargement 38. y, evident when the angle of taper at. thebottom of the countenbore becomes either too large or too small.

In practice, the rivets should be specified according to the distance desired between the. two

grips, as this automatically determines the proper h th of b the '32 hhier er q section [8. I

Thebul-bous enlargement t8; provides twoannular shoulders 46- and (l2 adjacent the inner s ei b it rlem rs vane 'Fheee he l e 6 e t ihe h' wit the eformed head 1 4 audit-he tulip shaped tail enlargeh h 3 e sl h. e h ee f en l r e Whieh is ex mely rQh5h l i9h 1 eeertes To secure the ass embled rivet, itis necessary nl e rzl e eeretih o c e re eleeetween t e r erm r e he e-hd the engagement head 30 on the mandrelf This fe f l e e th er hihah ehe el 'heth ie h re feeeemhlr "eh eh ihethe Sleeve 2 an i et body "l he rhh dr l he e hh iee d e heh 4. eh e W rk n ho d r; firee ehe hle er expeh ihe t riv beer 0. terreriee, the h ehe erhehfifi between he Well m mber --32 and 34'. This working shoulder and body portion t m nd l pa se hrou h he i 6 f l5..$f 9 s the Pul g i 28 s ubs que ly e vered a th l ew f t or n s oulder 56 and th p T b e th ma d l als has ape tieh f here eed d amet eewh eh di rs ehlv s ht y from the smaller diameter 44 and which prgvides e werh h sh lder 5 ie eh e e th ta l h he of he rivet T i is ma heee ear h t e stretching which occurs as a result of passing ege a la g w en o t mandrel .Zfi threhah Without this slight increasev in h i r 4 W r, r. diameter, that portion of the rivet body 10 passing' through the inner wallmer'nbe r 32. would not be forced into intimate contact there-with:- a

result the rivet would eventuaily becoriie loose and its inner grip weakened or rendered eygiy inefiective.

The large diameter 48 of the mandrelalso has a working shoulder 54 responsible tail end of the rivet.

As described and illustrated, the rivet is essentially of the plug type; however, the formi r g mandrel may be removed if weight rather" strength is the primary consideration. To e m mova ea e im'te "ferr te hee t of the tail e d h e lte the hi e? ha heeh fully expanded.

The'r'elative dimensions of the various elements comprising. the rivet lassemb ly are for the part dictated entirely by the genera l rei iuirements Q ll w l'kr- I y A "v. "7 h Th re are, however, iundamenta-Lconsidera e e hfehe h r h eh lth gene These same l -53 1916 E59. P SQH Q sembly. These are the columnar strength of the shank l2 and the tensile strength of the pulling pin 28. The former must be adequate to resist collapse as the mandrel 26 is drawn into position while the latter must be sufficient to withstand the force applied at the pulling head 30. These considerations are fundamental to the problem 0.1 iv t es nd a l h. h mini m ewessections which may characterize either. the rivet shank l2 or the pulling pin 28 for any given grip separation.

Although this invention was described with reference to the details of a particular modification it iriust be appreciated that the principles involved are susceptible of numerous other applications which will become apparent to persons skilled. i theert Having thus described the invention, what I desire to claim as new and secure by Letters Patent is:

1. A rivet assembly comprising a rivet body having a preformed head atone 'endthereofand a double' diametral axial bore therethroughf'an annular. tapered shoulder. in the axial here at the juncture of the two diameters, an'expafidable cylindrical sleeve received by the bore'and s, b on the tapered shoulder, andv a' mandrellhaving spaced working shoulders receivedby the ,lboffiej n the sleeve and efiective't o .expand'ispaced sections of the rivet.

2. A rivet assembly comprising arivetbody having a preformed head at 'one'endTthereE f'and a double diametral axial borel therethrough, the" smailer diameter of which occurs at tl i'e' 'frivt head, an annular taperedshoulder 'in the-axial bore at the iuncture'of the-two diameters, an'ex pandable cylindrical sleeve in" the axial""bbre seated on the tapered shq'ulder, and a pullingpin. in the axial bore having a pulling head Ithe redii outsidethe rivet head, and afo'rmin'g" mandrel on the opposite end thereof.

3. n rivetassembly comprising a hollow rivet body having an integrally fprrriedih'ead 'atone end thereof and a counterbore 'at' the opposite or tailv end extending axially to an annular "tat-1 pered shoulder, a cylindrical sleeveinthe: ceui pjerbore seated on the tapered'shoulder; [a 'piil'ling pin in the axial Rhfifi e p vi ed v hee ee ie and hollow rivet body, a rormmg'mend'r'ei o ri'the Pulling pin having spaced working shoulders for cooperation with thesle'eve and rivefsuce'ssively, and a gripping means' on me'punmgpiii'b 'nd the rivet head whereby an axial force may'be np q .7 l. s

4. A rivet assembly comprising a hollow rivet body having an integral prey-formed hadf at one end thereof anqafi'c unterbbre at thetpiq'q'sn or 'tail end extending to an annula nereeehehh eh e yhhd el le ve h he eehhte e se te h th teh ed eheulde i a pu lin p n in the axial ssa e pv d d by e e nr drical sleeveand htnptv rivet odyla forming Khhhrel eri e h e hv ih t emes hfl ea m h e h huhi'h -1 'herehe 'd' e eeiefw ere y a axial e ee have ehhhesl t9 dr w i e-hiefi relihtqt e a eh h e-e ee e eh r vet P v- 1-h rive *93Y2P1Y99Q9iiill h e-W rivet. e? her he 4 'htee el ec ermed head at hereei hee eehh erbere ettheqrineehe 9 g erieheihe re l t e he s, ehe lsl h e-erlihqhe eere. the ee ht n her-e eated h the a ere eh ulsler a ullin 15hr h I t axl p e hlt h r Perha s/heeded l r le rlahahql htii fireiih qrl h lhihe maa rel on the pulling pin adjacent the rivet tail, said mandrel being adapted to form an enlargement on the rivet tail and provide an expanded section on the rivet body when drawn by the pulling pin, and an engagement head on the pulling pin beyond the pre-formed rivet head whereby an axial force may be applied to draw the mandrel into the assembled sleeve and rivet body.

6. A rivet assembly comprising a hollow rivet body having an integral pre-formed head at one end thereof and a counterbore at the opposite or tail end extending axially to an annular tapered shoulder, a cylindrical sleeve in the counterbore seated on the tapered shoulder, a pulling pin in the axial passage provided by the cylindrical sleeve and hollow rivet body, a forming mandrel on the pulling pin having spaced working shoulders, and an engagement head on the pulling pin beyond the pre-formed rivet head whereby an axial force may be applied to draw the mandrel into the assembled sleeve and rivet body, said mandrel being adapted to expand first the sleeve and the rivet and then the free end of the rivet.

7. A rivet assembly comprising a hollow rivet body having an integral pre-formed head at one end thereof and a counterbore at the opposite or tail end extending axially to an annular tapered shoulder, a cylindrical sleeve in the counterbore seated on the tapered shoulder, a pulling pin in the axial passage provided by the cylindrical sleeve and hollow rivet body, a forming mandrel on the pulling pin having spaced working shoulders, and an engagement head on the pulling pin beyond the pre-formed rivet head whereby an axial force may be applied to draw the mandrel into the assembled sleeve and rivet body to expand spaced sections of the rivet, said mandrel being adapted for severance at the pre-formed head after the rivet body has been completely expanded.

8. A rivet assembly comprising a hollow rivet body having an integral pre-formed head at one end thereof and a counterbore at the opposite or tail end extending axially to an annular tapered shoulder, an expandable cylindrical sleeve in the counterbore seated against the tapered shoulder, a pulling pin in the axial passage provided by the assembled sleeve and hollow rivet body, a mandrel formed coaxial and integral with the pulling pin and extending beyond the rivet tail, said mandrel having three distinct forming shoulders the smallest being adapted to provide an expanded or bulbous section intermediate the rivet ends, the largest designed to provide a tail enlargement and the intermediate diameter calculated to expand slightly the section between the first two enlargements, said expansion and enlargements to occur when the mandrel is drawn into the rivet assembly, and an engagement head on the pulling pin beyond the pre-formed rivet head whereby an axial force may be applied to draw the forming mandrel into the assembled sleeve and rivet body.

WILLIAM W. SINGLETON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,061,629 Huck Nov. 24, 1936 2,195,029 Hathorn Mar. 26, 1940 2,248,755 Hathorn July 8, 1941 2,370,776 Carlson Mar. 6, 1945 FOREIGN PATENTS Number Country Date 472,329 Great Britain Sept. 22, 1937 536,476 Great Britain May 15, 1941 

